Navigation instrument



April 22, 1952 WEST 2,593,509

NAVIGATION INSTRUMENT Filed D80. 8, 1948 GYRO-COMPASS" ROTATES COMPASSCARDIZ ON CENTER 25 RUDDER CONTROL ROTATES POINTER !4 ON CENTER 25INVENTOR.

JUSTON w. WEST ATTORNEY Patented Apr. 22, 1952 UNITE STATES PATENTOFFICE NAVIGATION INSTRUMENT .lustcn W. West, Jenkintown, Pa.

Application December 8, 1948, Serial No. 64,064

The invention described herein may be manufactured and used by or forthe Government of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor. t

The present invention pertains to the art of navigation, and it isembodied in an instrument for navigating a navigable vehicle. Moreparticularly, the disclosed embodiment of the invention may be used inan aircraft, and comprises a flight control instrument by means of whichthe navigator or pilot of the vehicle is guided in a turn when hedesires to change the course of the aircraft, and thereby is better ableto direct the flight of the aircraft on the desired course.

An object of the invention is to provide an indicating instrument thatcombines the indicating features of a gyro-compass and a rateof-turnindicator.

Another object of the invention is to provide a flight instrument inwhich the indicator hand of a rate-of-turn indicator is mounted forregistration with the compass card of a gyro-compass.

The single figure of the drawing is a frontal view of a preferredembodiment of aninstrument that constitutes the invention, the Viewbeing partially schematic.

The instrument of the disclosure comprises a casing II which 'may beinstalled in any conventional manner in a navigable vehicle such as anaircraft for example, and preferably the casing II is mounted on theinstrument panel of the aircraft. The casing II houses the compass cardI2, which is rotatable on center 25 in ac-- cordance with conventionalpractice to maintain a position in which it points towards and indicatesnorth. According to conventional modern practice the compass card I2 isdriven to rotate by means of a gyro-compass I3, illustrateddiagrammatically in the drawing at IT.

Rotation of the compass card I2 is with reference to the vehicle inwhich the gyroec ompass I1 is installed, and with reference to thecasing or housing II for the compass card, the housing I I being securedin the vehicle. as usaul in fixed position on the instrument panel. Thecompass card I2 comprises an arcuate scale of iridica I8 divided intoangular increments. In the instrument specifically disclosed, which isfamiliar to pilots, navigators and the like personnel engaged in theoperation of aircraft, there are two similar and corresponding arcuatescales I8 and I 9 of indicia, which are concentric and are radiallydisplaced with reference to each other, the scales I 8 and I9 beingcoaxial with the axis 25 of rotation of the compass card.

The housing II comprises the face 28 which masks arcuate portions of thetwo scales I3 and I9, and comprises windows 2! and 22 that leave aportion only of each of the scales I8 and I9 1 Glaim. (Cl. 116129)exposed, the portions of the several scales I8 and I9 exposed by windows2I and 22 respectively being on respective opposite sides of the center25 of compass card I2. The Window 2| comprises the pointer I-B which ispositioned on the housing I I to indicate the, heading of the aircraft,and is positioned with reference to the compass card I2 to sweep thescale I8. The pointer I6 being fixed with reference to the vehicle, andthe 0 mark of the scale I8 being always directed to- .wards thegeographic north, the indicium of scale I8 to which the pointer I6 isdirected indicates the geographic heading of the vehicle.

Within casing II is a rate-of-turn indicator hand or pointer I4, whichis rotatable on the center 25 of the compass card I2, and of the scaleI8 which it sweeps, the pointer-I4 being driven to rotate with referenceto the pointer I6. Drive of the pointer I4 is by whatever apparatus iscontained; in the vehicle to navigate it and steer it along the desiredcourse. In the case of the disclosed aircraft navigation for example,pointer I4-is connected with the rudder and the rudder control, as isindicated diagrammatically at I5.

The compass I! that operates the compass card I2, and mechanism I5 thatdrives the rotatable pointer I4, may be in close proximity to theinstrument housing I I, or may be positioned at a remote location of theaircraft, and connected respectively with the compass card I2 and themovable pointer I4 in conventional manner for remote operation.

Pointer I-l positioned to register with the fixed pointer I6 indicatesthat the aircraft is headed as desired on a straight course, and thatthere is no rudder control. Pointer I6 is "operated under ruddercontrolto rotate by an amount that indicates themagni-tude of ruddercontrol that is appliedby'the pilotto-make a turn for the desired changeof course.-i "j In operation with 'an aircraft infiight, pointer Itpoints to anindicium of the scale I8 of the pointer I6. For example, asshown in the drawing, fixed pointer l6 registers with compass card I2 toindicate a heading of 30 to the east of north. Rate-of-turn indicatorhand I4, as shown in its solid line position, is in registration withpointer I6, and indicates that the aircraft is flying a straight courseand is not turning.

In the event that the pilot of the aircraft desires to execute a turn,be operates the rudder control in the usual manner for the desired turn.The rate-of-turn indicator hand I 4 thereby ,is angularly displaced awayfrom pointer I6 in the direction corresponding to the direction of turninstituted by the pilot. The pilot sets the magnitude of rudder controlfor making a turn in ac cordance with the rate of turn he desires forthe particular navigation undertaken. If the pilot wishes to turnsharply, he sets a greater magnitude of rudder control than when hedesires a slower turn. The degree of displacement of pointer l4 from thepointer It varies in accordance with the magnitude of turn controlinstituted by the pilot, and therefore the angular displacement of thepointer l4 away from the fixed pointer I6 is a measure of the rate ofturn of the aircraft. For example, as shown in the drawing, the dottedline position of rate-of-turn indicator hand l4 shows that the aircraftis executing a turn to the right, and the fact that rate-of-turnindicator hand [4 is angularly displaced away from fixed pointer Hi to arelatively great degree indicates that a relatively rapid turn is beingexecuted.

As the turn instituted by the pilot progresses, the compass card l2rotates relative to the case H, and relative to the fixed pointer It, inaccordance with the changing direction of flight, and the direction offlight currently at any time during the execution of the turn is therebyindicated on the scale It! by the pointer Hi. When the pointer I iapproaches the new direction @of flight desired by the pilot for whichhe executed the turn, the pilot changes the turn control towardsstraight course, and he so navigates the aircraft until the fixedpointer It indicates the desired new direction of flight. By operatingthe turn controls towards straight course, the rateof-turn pointer Mrotates away from its dotted line position towards registry with fixedpointer l6, and the pilot operates the rudder control to bring thepointer l4 into registry with the fixed pointer [6 at the same time whenthe pointer 16 indicates the desired new direction of flight on thecompass card I2.

The flight instrument of the present invention may be used to maintainflight along a straight course by keeping the rate-of-turn indicatorhand M in registration with pointer it through rudder action. If theaircraft yaws, the rate-ofturn indicator hand M and the compass card 12move out of registration with fixed pointer H in opposite directions,and correction for the yaw to bring the aircraft back on proper courseis easily effected by applying rudder control that operates to bring therate-of-turn indicator hand 14 back into registration with the propercourse. With this procedure the proper course is regained or retained bythe pilots single action and thought of keeping the indicator hand 14 onthe proper course indication of the compass card 12.

If it is desired to change the course of the aircraft, a properlyexecuted turn may be made through rudder action by angularly displacingrate-of-turn indicator hand M from registration with pointer l5 and theoriginal course marking of compass card [2 to a new position withrespect lat to compass card l2 corresponding with the new course. Forexample, referring to the drawing, assume that the aircraft is flying astraight course along a heading of 30 and it i desired to turn theaircraft into a new heading of The original course of 30 is indicated bythe pointer I6 registering with the 30 marking compass card l2, and thefact that a straight course is being flown is indicated by therate-ofturnindicator hand l4 being in the full line tion of the drawingin registry with pointer it. To execute the turn and bring the aircraftinto the desired new course, the aircraft is given right ruddersufiiciently so that rate-of-turn indicator hand I4 is displacedangularly onto the dotted line position of registration with the 60marking of compass card 12, and the rudder control is held to maintainthe movable pointer i in this position. As the aircraft gradually turnsinto the new heading, the compass card. l2 rotates counter-clockwise andthe pointer it progresses in a clockwise direction with respect tocompass card l2 until it is in registration with the 60 marking ofcompass card [2. While the turn progresses towards and approaches thedesired 6% heading, as indicated by fixed pointer Hi approaching the 60marking of compass card 52,

ier

the pilot applies rudder control towards in position of straight coursethat operates to s the pointer I4 counter-clockwise, and he times thisstraightening rudder control to bring the pointers I4 and It in registrywith each other at the same time when pointer It indicates the desirednew 60 course on the compass card i which indicates straight flight onthe desired new heading.

I claim:

In a navigation instrument for a navigable vehicle, a compass cardrotatable to hold a position that indicates north and comprising acoaxial arcuate scale of indicia divided into angular increments, apointer positioned with reference to the compass card to sweep the scaleof indicia and positioned fixed with reference to the vehicle toindicate its heading, a pointer rotatable relative to the compass cardon an axis coaxial therewith to sweep the scale, the rotatable pointerbeing rotatable relative to the fixed pointer in accordance with themagnitude of turning control imposed upon the vehicle to steer it to anew course.

JUSTON W. WEST.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,900,709 Henderson Mar. 7, 19332,276,717 Codebecq Mar. 17, 1942 2,413,214 Carlson Dec. 24, 1946

